We currently need 'vzctl exec' for net stats which is clumsy.
And the blkio stats for container does not seem to deliver
correct values.

We now have fully functional openvz vnc console.

And add start/stop/shutdown/remove/console buttons.

test if /etc/pve is mounted; else simple exit

I.e. when vzctl package is not installed.

That code is too unstable, so we disable that for now.